(log|lock)daemon: Don't spam logs with IO error messages after client disconnects

(log|lock)daemon: Don't spam logs with IO error messages after client disconnects

The log and lock protocol don't have an extra handshake to close the
connection. Instead they just close the socket. Unfortunately that
resulted into a lot of spurious garbage logged to the system log files:

2017-03-17 14:00:09.730+0000: 4714: error : virNetSocketReadWire:1800 : End of file while reading data: Input/output error

or in the journal as:

Mar 13 16:19:33 xxxx virtlogd[32360]: End of file while reading data: Input/output error

Use the new facility in the netserverclient to suppress the IO error
report from the virNetSocket layer.